Ah In, who has never been in a relationship, hopes to be with her secret crush who is working together. Ji Yoo, seeking free love, decided to go back to school to get over people’ rough eyes. Eventhough, Ha Young is in 4 years of a relationship with a guy from the same school and is envied by others, she experiences coldness with him. These three get into the same group in the summer class "Sex and Love." They all have different personalities, dating styles, and perspectives on sex, which bring about conflicts....